Looking for a way of calculating the maximum weight (W) to the rod with the given length (L) where the rod did not break and that only bend for (b) mm.

Need only approximative solution (read: simple as possible :), nothing with finite-elements or integrals or so.

The practical background: What rod i should to use for suspension of 100kg with L=1.5m and max bending approx. b=1cm? For what constants should I looking for in the published "properties" for the different materials and different profiles? E.g. steel rod vs bamboo? :)

While this is a topic in physics, you will find the best practical instructions in the second half of any engineering "Statics" textbook you care to look in. Further search terms that might help include "stress", "strain", "point-load", and "deflection" in various combinations.
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dmckee♦Jan 30 '12 at 18:26